Many data communication systems use error correction encoders and decoders to detect and correct errors in data. A data communication system may, for example, correct random errors that are generated at a rate of about 1×10−4. To protect against an error rate of about 1×10−4, an error correction encoder generates encoded bits having about 10% more bits than its input bits.
Phase change memory (PCM) is a class of non-volatile memory. PCM devices have many advantages over traditional non-volatile flash memory. However, PCM devices may generate a large number of errors that are induced by degradation. For example, a PCM device may generate errors at a rate of 1×10−2 or greater.
At the limits of endurance, the error rate in non-volatile memory devices is dominated by degradation. Errors that are caused by degradation include stuck-at faults, which have different statistics than the random errors that are common in data communication systems.